In a wireless network, data may travel from a wired network to mobile devices via base stations or directly between wireless users via radio or infrared waves. Data moves between client adapters in the mobile devices and access points throughout the network. An access point is a wireless device that serves as a bridge between wired and wireless networks.
The IEEE 802.11 standard, published Jun. 26, 1997, is a wireless LAN (Local Area Network) standard that specifies an “over the air” interface between a wireless station (mobile device) and an access point, as well as among other wireless stations. IEEE 802.11 defines two network configurations: an infrastructure configuration and an independent, or ad hoc, configuration. In the infrastructure configuration, clients communicate to access points, which are part of a distribution system having an infrastructure. In the ad hoc configuration, wireless stations communicate directly to each other, without the need for a communications infrastructure. However, coverage is limited to the radio (or IR) range of the wireless stations in the ad hoc network.
Wireless stations require an antenna and a 802.11 network interface. Wireless stations in the networks may include different types of mobile devices, for example, a laptop or desktop computer with a wireless modem, or a network-enabled mobile telephone or Personal Digital Assistant (PDA). A mobile device with an 802.11 network interface may operate in one of two communication modes, which correspond to the two network configurations. In an infrastructure mode, the wireless station may communicate with the infrastructure network via an access point. In an ad hoc mode, the wireless station may communicate with other mobile devices within range of the station's antenna.